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Georgopoulos D, Bolaki M, Stamatopoulou V, Akoumianaki E. Respiratory drive: a journey from health to disease. J Intensive Care 2024; 12:15. [PMID: 38650047 DOI: 10.1186/s40560-024-00731-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
Respiratory drive is defined as the intensity of respiratory centers output during the breath and is primarily affected by cortical and chemical feedback mechanisms. During the involuntary act of breathing, chemical feedback, primarily mediated through CO2, is the main determinant of respiratory drive. Respiratory drive travels through neural pathways to respiratory muscles, which execute the breathing process and generate inspiratory flow (inspiratory flow-generation pathway). In a healthy state, inspiratory flow-generation pathway is intact, and thus respiratory drive is satisfied by the rate of volume increase, expressed by mean inspiratory flow, which in turn determines tidal volume. In this review, we will explain the pathophysiology of altered respiratory drive by analyzing the respiratory centers response to arterial partial pressure of CO2 (PaCO2) changes. Both high and low respiratory drive have been associated with several adverse effects in critically ill patients. Hence, it is crucial to understand what alters the respiratory drive. Changes in respiratory drive can be explained by simultaneously considering the (1) ventilatory demands, as dictated by respiratory centers activity to CO2 (brain curve); (2) actual ventilatory response to CO2 (ventilation curve); and (3) metabolic hyperbola. During critical illness, multiple mechanisms affect the brain and ventilation curves, as well as metabolic hyperbola, leading to considerable alterations in respiratory drive. In critically ill patients the inspiratory flow-generation pathway is invariably compromised at various levels. Consequently, mean inspiratory flow and tidal volume do not correspond to respiratory drive, and at a given PaCO2, the actual ventilation is less than ventilatory demands, creating a dissociation between brain and ventilation curves. Since the metabolic hyperbola is one of the two variables that determine PaCO2 (the other being the ventilation curve), its upward or downward movements increase or decrease respiratory drive, respectively. Mechanical ventilation indirectly influences respiratory drive by modifying PaCO2 levels through alterations in various parameters of the ventilation curve and metabolic hyperbola. Understanding the diverse factors that modulate respiratory drive at the bedside could enhance clinical assessment and the management of both the patient and the ventilator.
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Affiliation(s)
| | - Maria Bolaki
- Department of Intensive Care Medicine, University Hospital of Heraklion, Heraklion, Crete, Greece
| | - Vaia Stamatopoulou
- Department of Pulmonary Medicine, University Hospital of Heraklion, Heraklion , Crete, Greece
| | - Evangelia Akoumianaki
- Medical School, University of Crete, Heraklion, Crete, Greece
- Department of Intensive Care Medicine, University Hospital of Heraklion, Heraklion, Crete, Greece
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Hao X, Yang Y, Liu J, Zhang D, Ou M, Ke B, Zhu T, Zhou C. The Modulation by Anesthetics and Analgesics of Respiratory Rhythm in the Nervous System. Curr Neuropharmacol 2024; 22:217-240. [PMID: 37563812 PMCID: PMC10788885 DOI: 10.2174/1570159x21666230810110901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/27/2023] [Accepted: 02/28/2023] [Indexed: 08/12/2023] Open
Abstract
Rhythmic eupneic breathing in mammals depends on the coordinated activities of the neural system that sends cranial and spinal motor outputs to respiratory muscles. These outputs modulate lung ventilation and adjust respiratory airflow, which depends on the upper airway patency and ventilatory musculature. Anesthetics are widely used in clinical practice worldwide. In addition to clinically necessary pharmacological effects, respiratory depression is a critical side effect induced by most general anesthetics. Therefore, understanding how general anesthetics modulate the respiratory system is important for the development of safer general anesthetics. Currently used volatile anesthetics and most intravenous anesthetics induce inhibitory effects on respiratory outputs. Various general anesthetics produce differential effects on respiratory characteristics, including the respiratory rate, tidal volume, airway resistance, and ventilatory response. At the cellular and molecular levels, the mechanisms underlying anesthetic-induced breathing depression mainly include modulation of synaptic transmission of ligand-gated ionotropic receptors (e.g., γ-aminobutyric acid, N-methyl-D-aspartate, and nicotinic acetylcholine receptors) and ion channels (e.g., voltage-gated sodium, calcium, and potassium channels, two-pore domain potassium channels, and sodium leak channels), which affect neuronal firing in brainstem respiratory and peripheral chemoreceptor areas. The present review comprehensively summarizes the modulation of the respiratory system by clinically used general anesthetics, including the effects at the molecular, cellular, anatomic, and behavioral levels. Specifically, analgesics, such as opioids, which cause respiratory depression and the "opioid crisis", are discussed. Finally, underlying strategies of respiratory stimulation that target general anesthetics and/or analgesics are summarized.
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Affiliation(s)
- Xuechao Hao
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yaoxin Yang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Jin Liu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Mengchan Ou
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Bowen Ke
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Cheng Zhou
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
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O’Donohoe PB, Turner PJ, Huskens N, Buckler KJ, Pandit JJ. Lack of influence of dexmedetomidine on rat glomus cell response to hypoxia, and on mouse acute hypoxic ventilatory response. J Anaesthesiol Clin Pharmacol 2021; 37:509-516. [PMID: 35340947 PMCID: PMC8944378 DOI: 10.4103/joacp.joacp_309_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 11/05/2022] Open
Abstract
Background and Aims There is a lack of basic science data on the effect of dexmedetomidine on the hypoxic chemosensory reflex with both depression and stimulation suggested. The primary aim of this study was to assess if dexmedetomidine inhibited the cellular response to hypoxia in rat carotid body glomus cells, the cells of the organs mediating acute hypoxic ventilatory response (AHVR). Additionally, we used a small sample of mice to assess if there was any large influence of subsedative doses of dexmedetomidine on AHVR. Material and Methods In the primary study, glomus cells isolated from neonatal rats were used to study the effect of 0.1 nM (n = 9) and 1 nM (n = 13) dexmedetomidine on hypoxia-elicited intracellular calcium [Ca2%]i influx using ratiometric fluorimetry. Secondarily, whole animal unrestrained plethysmography was used to study AHVR in a total of 8 age-matched C57BL6 mice, divided on successive days into two groups of four mice randomly assigned to receive sub-sedative doses of 5, 50, or 500 μg.kg-1 dexmedetomidine versus control in a crossover study design (total n = 12 exposures to drug with n = 12 controls). Results There was no effect of dexmedetomidine on the hypoxia-elicited increase in [Ca2%]i in glomus cells (a mean ± SEM increase of 95 ± 32 nM from baseline with control hypoxia, 124 ± 41 nM with 0.1 nM dexmedetomidine; P = 0.514). In intact mice, dexmedetomidine had no effect on baseline ventilation during air-breathing (4.01 ± 0.3 ml.g-1.min-1 in control and 2.99 ± 0.5 ml.g-1.min-1 with 500 μg.kg-1 dexmedetomidine, the highest dose; P = 0.081) or on AHVR (136 ± 19% increase from baseline in control, 152 ± 46% with 500 μg.kg-1 dexmedetomidine, the highest dose; P = 0.536). Conclusion Dexmedetomidine had no effect on the cellular responses to hypoxia. We conclude that it unlikely acts via inhibition of oxygen sensing at the glomus cell. The respiratory chemoreflex effects of this drug remain an open question. In our small sample of intact mice, hypoxic chemoreflex responses and basal breathing were preserved.
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Affiliation(s)
- Peadar B. O’Donohoe
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
- Nuffield Department of Anaesthetics, Oxford University Hospitals, Oxford OX3 9DU, UK
| | - Philip J. Turner
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Nicky Huskens
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Keith J. Buckler
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
| | - Jaideep J. Pandit
- Nuffield Department of Anaesthetics, Oxford University Hospitals, Oxford OX3 9DU, UK
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Vaporidi K, Akoumianaki E, Telias I, Goligher EC, Brochard L, Georgopoulos D. Respiratory Drive in Critically Ill Patients. Pathophysiology and Clinical Implications. Am J Respir Crit Care Med 2020; 201:20-32. [DOI: 10.1164/rccm.201903-0596so] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Katerina Vaporidi
- Department of Intensive Care Medicine, University Hospital of Heraklion, Medical School University of Crete, Heraklion, Greece
| | - Evangelia Akoumianaki
- Department of Intensive Care Medicine, University Hospital of Heraklion, Medical School University of Crete, Heraklion, Greece
| | - Irene Telias
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Center and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Ewan C. Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine, University Health Network, Toronto, Ontario, Canada; and
- Toronto General Hospital Research Institute, Toronto, Ontario, Canada
| | - Laurent Brochard
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Center and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Dimitris Georgopoulos
- Department of Intensive Care Medicine, University Hospital of Heraklion, Medical School University of Crete, Heraklion, Greece
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O'Donohoe PB, Turner PJ, Huskens N, Buckler KJ, Pandit JJ. Influence of propofol on isolated neonatal rat carotid body glomus cell response to hypoxia and hypercapnia. Respir Physiol Neurobiol 2018; 260:17-27. [PMID: 30389452 PMCID: PMC6336315 DOI: 10.1016/j.resp.2018.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/14/2018] [Accepted: 10/29/2018] [Indexed: 11/06/2022]
Abstract
The intravenous anaesthetic propofol acts directly on carotid body glomus cells to inhibit their response to hypoxia. Propofol acts via novel mechanisms, as we excluded action via its known target receptors (nicotinic, GABA-ergic, or K+ channel). Inhibition of the hypoxic response is clinically relevant in anaesthesia.
In humans the intravenous anaesthetic propofol depresses ventilatory responses to hypoxia and CO2. Animal studies suggest that this may in part be due to inhibition of synaptic transmission between chemoreceptor glomus cells of the carotid body and the afferent carotid sinus nerve. It is however unknown if propofol can also act directly on the glomus cell. Here we report that propofol can indeed inhibit intracellular Ca2+ responses to hypoxia and hypercapnia in isolated rat glomus cells. Neither this propofol effect, nor the glomus cell response to hypoxia in the absence of propofol, were influenced by GABA receptor activation (using GABA, muscimol and baclofen) or inhibition (using bicuculline and 5-aminovaleric acid). Suggesting that these effects of propofol are not mediated through GABA receptors. Propofol inhibited calcium responses to nicotine in glomus cells but the nicotinic antagonists vecuronium and methyllycaconitine did not inhibit calcium responses to hypoxia. TASK channel activity was not altered by propofol. The glomus cell Ca2+ response to depolarisation with 30 mM K+ was however modestly inhibited by propofol. In summary we conclude that propofol does have a direct effect upon hypoxia signalling in isolated type-1 cells and that this may be partially due to its ability to inhibit voltage gated Ca2+v channels. We also note that propofol has the capacity to supress glomus cell excitation via nicotinic receptors and may therefore also interfere with paracrine/autocrine cholinergic signalling in the intact organ. The effects of propofol on chemoreceptor function are however clearly complex and require further investigation.
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Affiliation(s)
- Peadar B O'Donohoe
- Department of Physiology, Anatomy & Genetics, Parks Road, University of Oxford, Oxford, OX1 3PT, UK; Nuffield Department of Anaesthetics, Oxford University Hospitals NHS Trust, Oxford, OX3 9DU, UK
| | - Philip J Turner
- Department of Physiology, Anatomy & Genetics, Parks Road, University of Oxford, Oxford, OX1 3PT, UK
| | - Nicky Huskens
- Department of Physiology, Anatomy & Genetics, Parks Road, University of Oxford, Oxford, OX1 3PT, UK
| | - Keith J Buckler
- Department of Physiology, Anatomy & Genetics, Parks Road, University of Oxford, Oxford, OX1 3PT, UK
| | - Jaideep J Pandit
- Nuffield Department of Anaesthetics, Oxford University Hospitals NHS Trust, Oxford, OX3 9DU, UK.
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Stuth EAE, Stucke AG, Zuperku EJ. Effects of anesthetics, sedatives, and opioids on ventilatory control. Compr Physiol 2013; 2:2281-367. [PMID: 23720250 DOI: 10.1002/cphy.c100061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
This article provides a comprehensive, up to date summary of the effects of volatile, gaseous, and intravenous anesthetics and opioid agonists on ventilatory control. Emphasis is placed on data from human studies. Further mechanistic insights are provided by in vivo and in vitro data from other mammalian species. The focus is on the effects of clinically relevant agonist concentrations and studies using pharmacological, that is, supraclinical agonist concentrations are de-emphasized or excluded.
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Affiliation(s)
- Eckehard A E Stuth
- Medical College of Wisconsin, Anesthesia Research Service, Zablocki VA Medical Center, Milwaukee, Wisconsin, USA.
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Guerri-Guttenberg RA, Siaba-Serrate F, Cacheiro FJ. [Clinical relevance of cardiopulmonary reflexes in anesthesiology]. REVISTA ESPANOLA DE ANESTESIOLOGIA Y REANIMACION 2013; 60:448-456. [PMID: 23121709 DOI: 10.1016/j.redar.2012.09.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 08/31/2012] [Accepted: 09/08/2012] [Indexed: 06/01/2023]
Abstract
The baroreflex, chemoreflex, pulmonary reflexes, Bezold-Jarisch and Bainbridge reflexes and their interaction with local mechanisms, are a demonstration of the richness of cardiovascular responses that occur in human beings. As well as these, the anesthesiologist must contend with other variables that interact by attenuating or accentuating cardiopulmonary reflexes such as, anesthetic drugs, surgical manipulation, and patient positioning. In the present article we review these reflexes and their clinical relevance in anesthesiology.
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Affiliation(s)
- R A Guerri-Guttenberg
- Departamento de Anestesiología, Hospital Universitario Austral, Pilar, Buenos Aires, Argentina
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Low-dose dexmedetomidine facilitates the carotid body response to low oxygen tension in vitro via α2-adrenergic receptor activation in rabbits. Eur J Anaesthesiol 2012; 29:570-6. [DOI: 10.1097/eja.0b013e328356fba5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Teppema LJ, Baby S. Anesthetics and control of breathing. Respir Physiol Neurobiol 2011; 177:80-92. [PMID: 21514403 DOI: 10.1016/j.resp.2011.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 04/04/2011] [Accepted: 04/07/2011] [Indexed: 12/18/2022]
Abstract
An important side effect of general anesthetics is respiratory depression. Anesthetics have multiple membrane targets of which ionotropic receptors such as gamma-aminobutyric acid-A (GABA(A)), glycine, N-methyl-D-aspartate and nicotinic acetylcholinergic (nACh) receptors are important members. GABA, glutamate and ACh are crucial neurotransmitters in the respiratory neuronal network, and the ability of anesthetics to modulate their release and interact with their receptors implies complex effects on respiration. Metabotropic receptors and intracellular proteins are other important targets for anesthetics suggesting complex effects on intracellular signaling pathways. Here we briefly overview the effects of general anesthetics on protein targets as far as these are relevant for respiratory control. Subsequently, we describe some methods with which the overall effect of anesthetics on the control of breathing can be measured, as well as some promising in vivo approaches to study their synaptic effects. Finally, we summarize the most important respiratory effects of volatile anesthetics in humans and animals and those of some intravenous anesthetics in animals.
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Affiliation(s)
- Luc J Teppema
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands.
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